I designed this for my Nerf Face Tracking Turret project on youtube.

It fits these Servos: https://www.amazon.com/gp/product/B07GRMRH1Q/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

The barrel receives a 1/8" vinyl tube for air supply on one end, and a nerf dart fits over the other end

Monoprice

Maker Select

No

No

might not need any, I always run 20%

Filament: https://www.amazon.com/YOYI-Filament-Dimensional-Eco-Friendly-Green/dp/B01M6WENG6/ref=sr_1_1?keywords=green+petg+YOYI&qid=1581230955&sr=8-1